Apparatus for manufacturing plastic articles



July 11, 1939. w. WARD APPARATUS FOR MANUFACTURING PLASTIC ARTICLES I Filed Nov. 2, 1936 2 Sheets-Sheet 1 Ezg. i.. 3-" 6" 1 22 25 v I A T I 7 7 Q) 25 L 27 1 3- 44 w Q 34 o z 18 4 INVENTOR,

J ATTORNEY July 11, 1939. w. WARD APPARATUS FOR MANUFACTURING PLASTIC ARTICLES Filed Nov. 2, 1936 2 Sheets-Sheet 2 BY /-e. W

ATTORNEY Patented July 11, 1939 UNITED STATES 7 APPARATUS FOR MANUFACTURING PLASTIC V ARTICLES Walter Ward, Oakland, Calif., assignor to Vi-Vac Concrete Pipe Company, a corporation of California I Application November 2, 1936, Serial No. 108,788

4 Claims.

This invention relates to an improved apparatus for manufacturing tubular or other suitably shaped articles from concrete or other analogous material.

Another object of my invention is to provide improved apparatus of the kind characterized by which concrete articles having increased density and comparatively free of air holes may be made.

Other and further objects of my invention will be pointed out hereinafter, indicated in the appended claims, or obvious to one skilled in the art upon an understanding of the present disclosure. For the purposes oijthis application I have elected to show herein certain forms and details of apparatus for manufacturing concrete pipe representative of my invention; it is under stood, however, that the embodiment of my invention herein shown and described is for the purpose of illustration only, and that therefore it is not to be regarded as exhaustive of the variations of the invention, nor is it to be given interpretation such as might have the effect of limiting the claims, short of the true and most comprehensive scope of the invention in the art.

In the accompanying drawings: f

Fig. 1 is a side elevation of concrete pipe manufacturing apparatus embodying the preferred form of my invention, showing the tank door in an open position.

Fig. 2 is a top plan view of the apparatus with the top of vacuum tank removed; and

Fig. 3 is a sectional view takenon the line 3--3 of Fig. 1. 7

Referring to the drawings, the numeral I designates a number of stationary concrete supports within which are imbedded upright metal posts 2. Encircling the metal posts are coil springs 3 which yieldably support a number of transversely extending joists 4. The upright posts 2 extend through oversize holes in the joists 4 and are provided with threaded ends for the attachment of nuts 5. supported on thejoists 4 is a vacuum tank 5 of any suitable shape and size having a hinged door 7 at one end thereof. Suitable means, such as a keeper 8 and a pivoted latch member 9, is provided for releasably holding the door "I in a closed position. The vacuum tank Bis preferably made from reenforced sheet metal, and its interior is closed to the outer atmosphere when the door I is tightly shut. Positioned within the vacuum tank are one or more concrete forms Suitably secured to and crete pipe, it is to be understood that suitable forms embodying shapes and constructions for making various other types of articles may be satisfactorily employed in practicing my invention. The forms hereinillustrated each comprise 5 inner and outer concentrically arranged vertical tubular members Hi and H. The outer tubular member H of ,each form is provided at its lower end with ,a number of outwardly disposed projectionsll which are firmly bolted to the bot- 11) tom of the tank 5. The lower end of the inner tubular member [0 is maintained in a fixed position with respect to the lower end of the outer tubular member ll by a spacing ring l2 which rests on the bottom of the tank. The upper end of the inner tubular .member ID is preferably formed with an outwardly disposed horizontal annular partl0a, and an upwardly extending part lob, while the upper end of the outer tubular member H is bent outwardly and upwardlyas at I la and l lb, the said tubular members being so formed at their upper ends to provide the, pipe which is cast therein with an enlarged end fittingof suitable shape and size. 'So that a form may "be conveniently removed from the '25 hardened concrete material forming the cast or molded pipe, the inner tubular member l0 is provided with a collapsible .construction of the kind now commonly used while the outer tubular'member II is also provided with a removable con- 0 struction of the usual kind.

. Secured in any suitable manner to the upwardly disposed part No of the outer tubular member II is an outwardly flared annular hopper 13 which is rigidly connected by an annular grating H! to an inverted cone-shaped guide member I5 which rests upon the upwardly disposed part It?) of the inner tubular member I9. The hopper 13 and the guide member [5 are so shaped and positioned that flowable concrete or plastic'40 material falling from a hopper or conveyor I6 onto the said guide member is directed into the annular space located within the tubular form.

Each of the pipe forms is supplied with concrete or plastic material by a movable conveyor It having flanged wheels ll which ride upon horizontally disposed rails l8 located in suitable positions in the upper areas of the tank 6. The side rails I8 are preferably welded to vertical side braces or reenforcing members l9 secured to the side walls of the tank, while the intermediate rails I8 are suspended from vertical bars 29 welded to similar braces or reenforcing members '2! at the top of said tank;

Pivotally attached as at 22 to the upp'erte'nds 55 of upright posts 23 (only one shown on the drawings) are a plurality of suitably connected rail supports 24 (only one shown) which are adapted to assume substantially horizontal positions with adjacent ends thereof resting on the tank 6. Suspended from the rail supports 24, as by pivoted straps or rods 25, are a number of rails 26 which are adaptedto be positioned in horizontal alignment with the rails 18 located inside the tank 6. The rails 26 constitute extensions for the rails l 8 and permit the conveyors IE to be moved to a loading station (not shown) where they may be filled with concrete or other plastic material. After the conveyors I6 are loaded with fiowable concrete or plastic material they. are moved into the tank 6 and positioned with their tapered discharge ends [6 directly over the center of the inverted conical-shaped guide members 15. So as to elevate the rails 26 and the rail supports 24 in order that the tank door 1 may be closed, suitable means is provided consisting of a reel 21 mounted on one of the posts 23, a cable 28 connected at its ends to the reel and to one of the rail supports, and a pulley 29 over which the said cable extends. By turning the handle of the reel 21 the cable 28 is wound thereon, thereby moving the rail supports 24 and the rails 26 to upwardly inclined positions as shown by the dotted lines of Fig. 1. A looped strap 21' is adapted to receive the handle of the reel to prevent the latters unwinding.

The dischage opening in the tapered end 16 of each conveyor 16 is controlled by a weighted plug or gate 30 which is suspended from an individual cable 3|. The cables 3| extend over suitably grooved rollers 32 mounted on cross members 33 secured to the top ends of the conveyors I6 and also over similar rollers 34 supported on brackets 35 secured to the tank 6. The ;cables 3| are detachably fastened as at rings 36 to a master cable 31 which is fastened at one end to a connecting rod 38. The connecting rod 38 extends into a suitably shaped casing 39 and is connected to a fitted piston 40 which divides the interior of the said easing into chambers 4i and 42, An opening at one end of the casing permits air to be withdrawn or expelled into the tank 6 from the chamber 41, while an opening in the opposite end of the casing to which a pipe 44 is connected permits airto enter chamber 42 under pressure from a suitable source. A valve 45 on the pipe 44 serves to control the admittance of air into chamber 42 of the casing 39, or automatic means of any well known kind may also be used. After a partial vacuum has been created inside the tank 6, as well as inside the forms In and II, by withdrawing air therefrom by suitable means such as a vacuum pump connected to a pipe 46 communicating with the interior of said tank, air under pressure is admitted into chamber 42 of the casing 39, thereby moving the piston 40 toward the door end of the tank. As the piston is thus actuated, the connecting rod 38, as well as the cables 31 and 3|, move with it, thereby causing the gates 30to be raised from the discharge openings in the tapered ends [6 of the conveyors [6. It is preferable to open the discharge openings in the conveyors gradually so as to permit a fairly thin and ring-shaped film of fiowable concrete or plastic material to flow downwardly over the peripheries of the gates 30 and onto the inclined sides of the latters associated inverted cone-shaped guide members 15. It is well known in the art that theremoval of excess air and water from the mass of plastic concrete material will considerably increase the mechanical strength of a product manufactured therefrom. So as to effectively cause the concrete material delivered by the conveyors I6 to be thoroughly exposed to the vacuum before entering the forms and thereby freed of excess moisture and air, I have made the guide members 15 in the shape of inverted cones so that the said concrete material may be increasingly spread and separated as it proceeds from the conveyors to the forms. The thorough exposure of concrete or plastic material in this manner to the vacuum enables the entrained air and excess moisture therein to be withdrawn prior to its entering the forms. The concrete or plastic material upon passing through the gratings I4 is further broken upand freed of any lumps which might be therein, thereby enabling the partial vacuum in the tank and forms to act upon any of the mass which had not previously been exposed.

Mounted in suitable bearings 41 secured to one of the joists 4 is a shaft 41 having a pulley 48 secured thereto which is operatively connected by a belt 49 to the drive shaft of a motor 50. Secured to the shaft 41 is a disc 51 having weights 52 secured thereto at only one side of its axis. The eccentric position of the weights 52 on the disc 51 causes the shaft 41 to be vibrated when it is rotated at a suitable speed. The belt 49 is preferably provided with expansible and contractible means of the usual kind to compensate for the vibration of the shaft. The vibration of the shaft is transferred to the tank 6 and to all of the various parts of the apparatus the latter supports, thus not only the tubular forms are agitated but also the conveyors 16 of the concrete or plastic material and the guide means IS. The agitation of the material while in the conveyors l6 and as it spreads and flows over the guide members 15 causes the release of air pockets, the reducing of the same to a plastic state, and the otherwise thorough mixing of its ingredients.

A vacuum gauge 53 indicates the degree of vacuum in the tank, while a valve controlled air inlet means 54 allows air to enter the tank to break the partial vacuum after the forms have been properly filled with concrete or plastic material.

In actual practice a suitable degree of vacuum is created in the tank 6 and inside the forms Ill and II before the discharge openings of the conveyors 16 are opened to allow the flow of the material therefrom. As the gates 30 are opened to commence the discharge of the concrete or plastic material onto the guide members I5, (or prior thereto if so desired), the motor 50 is started and continuously operated to cause the vibration of the tank, the guide members, the gratings 14, the forms and other parts of the apparatus during the period the forms are being filled. The previous evacuation of air from the interior ,of the forms prior to the deposit therein of the coricrete or plastic material and the confining of the said material in a vacuum during the entire time it flows from the conveyors to the forms, ob-' .viates any chance of air being entrained to proterially increased. After the forms are properly The completed lengths of pipe or other articles made in accordance with my invention are almost entirely free of the usual and undesirable indentations caused by presence of air pockets. The increased density of the pipes thus made renders them impervious to air or moisture, and otherwise strengthens them materially.

Having described my invention, what I claim is:

1. An apparatus of the kind descibed comprising a vacuum tank, means connected to said tank to remove the air therefrom, a conveyor movably supported within said tank for holding plastic material, the said conveyor having a discharge opening, gate means for controlling said discharge opening, an operating device for said gate means including a motor carried within said tank, means for controlling said motor operable outside said tank, a form or mold positioned in said tank in spaced relation to said conveyor, and guide means for directing the plastic material from the conveyor to said form or mold.

2. In an apparatus as set forth in claim 1, means for agitating the tank and its contents.

3. An apparatus of the kind described comprising a vacuum tank, means connected to said tank to remove the air therefrom, a plurality of conveyors movably supported Within said tank for holding plastic material, each of said conveyors having a discharge opening therein, gate means in each conveyor for controlling the discharge openings, a motor within said tank, connecting means between each of said gate means and said motor, means for controlling said motor, a plurality of forms or molds positioned in said tank in spaced relation to each of said conveyors, and guide means for each of said conveyors for directing the plastic material from the conveyors to said forms or molds.

4. In an apparatus as set forth in claim 3, means for agitating the tank and its contents.

WALTER WARD. 

